Camera Labs

Hey Guys ,
I have posted two videos on the issue :
http://www.youtube.com/watch?v=aUTZtQIwJ_M
http://www.youtube.com/watch?v=LLhZpLoyg_M

When zooming the 14-140 lens a slight brightness ( aperture ? ) fluctuation is observed on the captured video. It kind of flickers and the flick is captured on the video.

Also when it flickers an intermittent noise coming from the lens can be heard too. The noise is there when zooming , irrespective of whether video recording is on , also lens stabilization being on or off still the same.

The noise is really quiet , even quieter than general background noise but is there. I am little concerned about both the noise and image fluctuation as I will be using this hybrid camera to make some commercial videos.

The 14-140 lens seems fine otherwise , except a small rattle if shaked. The zoom is kinda stiff but that is probably normal.

I wonder if the lens is little screwed . Could anyone compare to their gh2 with 14-140 lens and see if they have the flick and the noise ?


[UPDATE]

I am still testing but seems like the noise above is most notable in Intelligent Auto Mode.

In Manual movie mode it makes less noise but the image flicker is still there. I may need to play with the image settings more...

Remember this lens does not have a constant aperture, so when zooming in the auto exposure modes, it may be forced to adjust it - which could be audible and visible.

To avoid the aperture changing, shoot in Creative Manual mode, choose Manual or Aperture Priority and select an f-number of f5.8 or bigger.

You may also be hearing the image stabilisation motors, so to eliminate them, switch off stabilisation and use a tripod.

Unfortunately, that won't completely eliminate the issue. The "problem" is that this is primarily a stills (photography) camera and lens (read: not designed to zoom while taking a photograph), not a motion picture camera and lens (which usually are designed to zoom during a shot), which only costs $1,500. As compared to, say, an AF100 ($5,000) and Red Pro 18-85mm ($10,000) which together cost ten times as much! Nevermind a Zeiss Master Zoom 16-110mm which, by itself, is $60,000!

If you really need to zoom during a shot, you're better off using a camera and lens designed specifically for video (like the HMC40). Alternatively, the 14-45mm (note: NOT the 14-42mm) and 45-200mm lenses have less of an issue because, individually, they cover a shorter focal length.

Mark

Hey Maestro ,

I dont have to zoom as i am learning ... But I returned a Canon t2i because of the non-constant aperture lens it came with ... now the GH2 ... with its "Video Lens" and internet hype the "the best video dslr" is a bit letting me down on the same thing...

Anyway .. my budget is 1300 eur on all equipment for stills and video. My other option was to get a 700 eur camera plus 700 eur camcorder but came under the impression that the GH2 is as good as a 700 consumer corder such as the Panasonic TM700 ( if that was the name ) . Plus this Tm700 seems to shoot 1080 resolution only .... that is too big for some things...

Unfortunately, as you've found out, that's not an advantage of the GH2 + 14-140mm kit. (Unlike, for example, auto-focus and moire which are.)



But "best (hybrid) video dslr" is not the same as "best video (only) camera".



The TM700 is a very good camcorder. The GH2 is a very good, large sensor, interchangeable lens, hybrid stills/video camera.

Different tools for different jobs - Mark

....its very difficult that u would find a zoom lens that have a constant aperture trough the entire range, even the pro lenses have a difference of 1-1.5 f stop from the start to the end. Such lenses are so expensive that u could buy Canon T2i and GH2 for the price.
invest in some fast primes, manual or af, u can do same great stuff with them for a low cost.